From time to time the net adopts a big idea. The collective intelligence absorbs a new concept and, for a while, no one talks about anything else. The latest idea is from the glamorous world of statistics. It's called "power law distribution" and it promises to explain how a tiny minority of websites get to be super-popular and the rest never make it past first base.

The last time statistics and I crossed swords properly was when I failed my O-level mathematics in 1979 so I won't be troubling you with a lot of detail here but, to summarise as best I can, the law describes the way that, in a list of websites organised by popularity, the top site will usually be twice as popular as the second, 10 times as popular as the tenth, one hundred times as popular as the 100th... and so on. Visualise the list using a graph and you'll see a curve falling away sharply from left to right and then leveling out almost to a straight line at a very low level.

A small number of really popular sites will be high on the curve at the left of the graph and almost all of the rest distributed quite evenly along the flattening line at the bottom. This is called a law because it's repeated all over the place - in fact, wherever a lot of people are able to choose from many options. Pretty much anything that has an audience and some competition will wind up somewhere on a graph like the one I describe and, by definition, since so few can be high on that curve, it's very very hard to get there. Becoming popular is difficult.

So far, so common sense. Everyone knows that some websites float to the top and are then quite difficult to displace. The difference with power law lies in the law bit. You might say "I fought the law and the law won". The power law describes the distribution of audience (or links or reviews or almost any measure of popularity) for a group of heavily interlinked properties (such as websites) in a way that permits no variation. Power laws of one kind or another have been known to economists and statisticians for a long time. This is the first time that this kind of thinking has been applied to audiences for weblogs, though.

This kind of statistical thinking can be pretty useful. Among other things, by exposing the patterns in otherwise opaque phenomena such as website popularity, it helps us to understand how we can intervene (and how we can't) to influence things - when you should jump in with a huge advertising budget and when you'd be wasting your money, for instance. But it also has negative effects. For instance, it makes it difficult to think about what else is important. The popularity or otherwise of your site is handily reduced to a formula.

Even the most egg-headed advocate of the power law is unlikely to suggest that it's enough to explain the way websites produce and share audiences - let alone relationships - but the bloggers have picked up on the idea and are busy turning it into a fully fledged meme. As ideas go it's bound to be a big hit. It offers an easy explanation of something so ineffable that it defies interpretation.

Richard Sennet, in his new book Respect: the Formation of Character in an Age of Inequality, reminds us that there's a lot going on outside the realm of statistics. In fact his thesis is that in societies (and in social systems such as the net), these statistical models can illuminate only a tiny part of the story and must remain entirely mute on the real business of connection, interdependence and mutuality. The power law enthusiasts have jumped onto a theory that focuses entirely on the mechanical operation of a massively interdependent system but these systems - the blogosphere, mailing lists, forums and newsgroups - are much more than machines. They cannot be reduced to a statistical model for the production of currency, popularity, "inbound links" or traffic.

This misdirection of energy is typical, though. We all do it in all areas of life. But it's a kind of frantic displacement activity. It's like trying to account for a very complex, higher order social phenomenon such as a city by counting the paving slabs and manhole covers. Sure we can learn something from these curves and distributions but this knowledge is unlikely to advance our understanding of human interdependence - how bonds of respect are made and broken. How, for instance, the inherently generous activity of blogging can influence our relationships, our personalities and our societies. How change can be effected.

For Sennet, these visible, statistical aspects of a society are the grease in the machine, not the machine itself. Discussing the invisible exchanges that make up the fabric of our social lives, he says: "Still, I don't believe mutual respect is merely a tool to grease the gears of society. This art has consequences for the people who practise it; exchange turns people outward - a stance which is necessary for the development of character."